Dosing devices for tapping bulk goods from a silo-like container are already known in which an outlet opening can be opened and closed by a slide valve moving along a straight line. Depending on the type of bulk goods, difficulties may arise due to the bulk goods tending to cake or adhere to the walls of the container, thereby preventing normal flow due to bridging. It appears that, on the one hand, even if the problem of irregular follow-up flow of the bulk goods may be lessened by having a larger outlet opening, the side gap opening created by the sliding movement along a straight line, on the other hand, is unfavorable when only small quantities are required.
In an efficient process for filling containers, sacks and the like with bulk goods, a quantity of goods must be discharged for rough dosing at a high rate within the shortest possible time. In the case of fine dosing or tare weight packing to an accurate weight, small quantities of bulk goods must be added or removed once or several times. This creates a problem due to the fact that both a large and small through-flow opening must be available. This requirement cannot be solved satisfactorily with conventional valve closures because, with the bulk goods unfavorably responding during their flow, the weight of the material column above the narrow side gap opening is supported by the conical wall of the hopper or adheres to it so that there is an increased tendency for the bulk goods to bridge when the bulk goods are discharged in only small doses.
The purpose of this invention is to improve a dosing device for bulk goods and make it suitable for discharging small quantities of such goods as well as discharging the goods at a high through-flow rate within a wide range when large quantities of goods are to be discharged within a short time while guaranteeing faultless follow-up flow of bulk goods even with such bulk goods tending to bridge.
Since the closure is designed in the form of two spherical cap halves, which can be pivoted towards each other, a large through-flow opening for bulk goods is obtainable when they are pivoted away from each other into the fully open position. Alternatively, small through-flow openings can also be made, positioned in the central drop area, that is at a vertical point above the vertical material column.
A further advantage, in comparison with the conventional slide valve closures, consists in the fact that a more compact construction can be achieved due to the absence of the sideways slide movement overhang. This allows space-saving mounting of a number of bulk goods containers next to each other.
It can be useful to provide a rotatable stirring and loosening device inside the hopper when bulk materials, which flow with difficulty, and which are known to have a greater tendency to bridging are handled. Such a stirring and loosening device together with an outlet valve moving in a straight line is described in DE 256 147. As distinct from this, the rotatable stirring and loosening device can in this present case extend to the central, lower area of the outlet opening of the spherical cap halves. This reliably counteracts bridging, in the case of bulk goods which flow with difficulty, down to the lowest area of the bulk goods containers, that is down to the spherical cap halves, and guarantees the follow-up flow of the goods even when only a small through-flow aperture is open.
A particularly compact layout facilitating maintenance work is achieved by designing the dosing device with a bearing ring attached at the bottom to a body and a swivel ring with a driving crane located in between.